How did the Treaty of Versailles return Alsace-Lorraine to France?

The Treaty of Versailles formally returned Alsace-Lorraine to France by establishing new national boundaries for Germany following its defeat in World War I.12

For French Prime Minister Georges Clemenceau, this retrocession was a significant achievement. Having personally protested the territory's annexation by Germany in 1871, Clemenceau viewed the return of Alsace-Lorraine as a matter of poetic justice. During the Paris Peace Conference, he navigated complex negotiations with Allied leaders to ensure the treaty reflected French interests, ultimately insisting that the document be signed in the Hall of Mirrors at the Palace of Versailles—the same location where the German Empire had been proclaimed nearly 50 years earlier.3